Collapsible chair

ABSTRACT

A folding chair which comprises a frame ( 100 ), a piece of cloth ( 400 ) and fastening and tensioning devices ( 430, 440 ). The seat side members ( 121   a,    121   b ) are telescopic and so arranged that a seat cross member ( 120 ) is movable. Straps ( 430, 440 ) extend around the chair frame ( 100 ) and preferably run over the members ( 110, 120, 131, 141 ) so as to hold the chair in an unfolded position. The straps, which transfer all tensile forces, are joined in a buckle ( 435 ) and are fastened to the members ( 110, 120, 131, 141 ) in such manner that the elements can rotate freely about the respective members.

[0001] The present application relates to chairs. More specifically, the invention relates to a folding chair according to the preamble of independent claim 1.

[0002] A myriad of folding chairs are known.

[0003] U.S. Pat. No. 4,685,725 describes a folding chair comprising a piece of fabric and bars. The piece of fabric is necessary in order to keep the chair in an unfolded state.

[0004] U.S. Pat. No. 4,836,601 describes a folding chair comprising bars and a piece of fabric.

[0005] U.S. Pat. No. 5,320,404 teaches a folding chair of lightweight bars and a piece of fabric which is stretched across the supporting bars.

[0006] GB 2 308 974 describes a system of bars which can be combined in a number of different ways in order to form, inter alia, a seating apparatus.

[0007] U.S. Pat. No. 3,123,395 relates to a folding chair having four U-shaped legs, where the side bars of each of the legs are rotatably interconnected by bolts in the respective sides of the chair. The chair has a canvas cover which at its upper and lower parts is suspended from transverse members, and straps hold the U-shaped legs together in an unfolded position.

[0008] However, the disadvantage of most folding chairs is that even when folded they are relatively bulky and hence rather unsuitable for transport in, e.g., a backpack or on a bicycle. The folding chairs which are quite compact when folded are unstable and/or uncomfortable to sit on when unfolded. Furthermore, the structures are in many cases unnecessarily complex and highly subject to wear and breakage.

[0009] Therefore, there is a need for a folding chair of the type described above, and as disclosed in the preamble of the attached claim 1. The folding chair according to the invention comprises a frame, a piece of cloth and fastening and tensioning devices, and further comprises:

[0010] a seat frame having two substantially parallel seat side members, pivotally interconnected at their respective first, outer ends to opposite respective ends of a substantially transverse seat cross member by means of respective swivelling corner joints, which said seat side members, at their respective second, inner ends, are pivotally connected to respective seat or combined joints;

[0011] a back frame comprising two substantially parallel back side members, pivotally interconnected at their respective first, upper ends to opposite respective ends of a substantially transverse back cross member by means of respective swivelling corner joints;

[0012] a front leg assembly comprising two substantially parallel front leg side members, pivotally interconnected at their respective, first lower ends to opposite respective ends of a substantially transverse front leg cross member by means of respective swivelling corner joints;

[0013] a rear leg assembly comprising two substantially parallel rear leg side members, pivotally interconnected at their respective, first lower ends to opposite respective ends of a substantially transverse rear leg cross member by means of respective swivelling corner joints, which said rear leg side members at their respective second, upper ends are pivotally connected to said respective seat or combined joints,

[0014] wherein the chair comprises tension-absorbing elements which extend around the chair frame and preferably run across said substantially transverse members so as to maintain the chair in an unfolded state.

[0015] The folding chair according to the invention is characterised in that:

[0016] said seat side members are telescopic and so arranged that said seat cross member is movable;

[0017] said corner joints comprise an offset corner joint with a pivot point which is drawn back some distance from the pivot point of a second corner joint; and

[0018] said seat frame, back frame, front and rear leg assemblies are all pivotally interconnected to substantially transverse members by means of swivelling joints.

[0019] Preferred features of the chair according to the invention are set forth in dependent claims 2 to 14.

[0020] Embodiments of the invention are set forth in the attached patent claims and in the following description with reference to the attached drawings. It should be understood that the drawings are merely typical exemplary embodiments, and should not be regarded as defining the limits of the invention. The same reference numerals are used to indicate the same parts in the drawings, and these are also used in the description below.

[0021]FIG. 1a is a perspective view of one embodiment of the chair according to the invention, and shows the chair when unfolded. The straps are shaded grey for illustrative purposes.

[0022]FIG. 1b is a second perspective view of the chair shown in FIG. 1a.

[0023]FIG. 1c is yet another perspective view of the chair shown in FIG. 1a and 1 b.

[0024]FIG. 2 is a perspective view of the chair shown in FIGS. 1a-1 c, but shown without the piece of cloth and straps for illustrative purposes.

[0025]FIG. 3a is a side view of the chair depicted in FIGS. 1a-c and FIG. 2, and shows in particular the combination joint.

[0026]FIG. 3b is a side view of a second embodiment of the chair according to the invention, where the seat is placed lower and the back is thus longer than in the embodiment depicted in FIG. 3a, and shows in particular the seat joint and the back joint.

[0027]FIGS. 4a-4 d are perspective views of the frame of the chair according to the invention (without the piece of cloth and straps for illustrative purposes) in different states. FIG. 4a shows the frame (the chair) when unfolded, FIGS. 4b and 4 c show intermediate stages, and FIG. 4d shows the frame when folded. The arrows A-F indicate the folding sequence.

[0028]FIGS. 5a and 5 b are perspective views of the chair according to the invention, where the frame is in a folded stated (cf FIG. 4d), and they also show the piece of cloth and the straps. FIG. 5b shows the chair according to the invention in its most compact form.

[0029]FIG. 6 is a perspective view of an embodiment of the chair according to the invention (without the piece of cloth and straps for illustrative purposes) in a partly folded state.

[0030]FIGS. 7a-7 c are respectively a plan view, a side view and an end view of the frame in a folded state.

[0031]FIG. 7d is a plan view of the telescopic seat members in extended and retracted states.

[0032]FIGS. 8a-8 c are different views of the combined joint and show the individual components.

[0033]FIG. 9 is a side view of the combined joint and parts of the connected frame members, and show the joint in a position where the frame is in an unfolded state.

[0034] The following parts are identified in the figures and the following description: 100 frame 110 back cross member 111a back side member - short 111b back side member - long 120 seat cross member 121a seat side member - short 121b seat side member - long 130a front leg side member - short 130b front leg side member - long 131 front leg cross member 140a rear leg side member - short 140b rear leg side member - long 141 rear leg cross member 150a offset corner joint 150b corner joint 190 seat joint 191 back joint 193 combined joint 193a main component 193b back component 193c seat/leg component 400 piece of cloth 410 seat portion 412 back portion 413 side faces 430 encircling straps 440 front cross straps 435 buckle

[0035] The folding chair according to the invention is very compact and has, when folded, a practical cylindrical form. In this state the total length corresponds to the width of the seat.

[0036] The construction consists of bars or members (tubes), joints and supports, telescopic seat side members (121 a, 121 b), straps (430, 440), a tension lock or buckle (435) for the straps, and a material (400), e.g., cloth or net, made in the form of a seat or “seating bag”. The “seating bag” is secured (passed onto) to horizontal members (110, 120), where one is at the front edge of the seat and the other is at the top of the back. These two horizontal members are held in position by a system of bars in the vertical and horizontal plane together with the straps.

[0037] The construction is based on a simple load image: bars in the vertical plane take pressure (collapsing forces). Horizontal members are subjected to bending forces. All tensile forces are transferred by means of the straps. Joints and supports are designed not to transfer bending moments. The straps behind the back and at the front under the seat are laid in a cross in order to take up bias and diagonal movements.

[0038] There are no loose parts and the whole construction is locked in the unfolded state using a single tension lock behind the back.

[0039] As mentioned, the chair comprises a frame (100), a piece of cloth (400) and fastening and tensioning devices. The piece of cloth (400) is typically adapted to form a seat portion (410), a back portion (412) and two side faces (413).

[0040] The structure of the chair will now be described in detail, and reference is first made to FIG. 1a, where the straps (430, 440) and the buckle (435) have been highlighted for illustrative purposes.

[0041] The seat frame comprises two substantially parallel seat side members (121 a, 121 b) pivotally interconnected at their respective first, outer ends to opposite respective ends of a seat cross member (120) by means of respective swivelling joints, offset corner joint (150 a) and corner joint (150 b) respectively. At their respective second, inner ends, the seat side members (121 a, 121 b) are pivotally connected to respective joints; in one embodiment a seat joint (190); and in a second embodiment a combined joint (193), which will be discussed below.

[0042] The back frame comprises two substantially parallel back side members (111 a, 111 b) pivotally interconnected at their respective first, upper ends to opposite respective ends of a substantially transverse member (110) by means of respective swivelling corner joints (150 a, 150 b). In one embodiment the back side members (111 a, 111 b) at their respective second, lower ends are pivotally connected to respective joints (191; 193).

[0043] The front leg assembly comprises two substantially parallel front leg side members (130 a, 130 b) pivotally interconnected at their respective first, lower ends to opposite respective ends of a substantially transverse member (131) by means of respective swivelling corner joints (150 a, 150 b). In one embodiment the front leg side members (130 a, 130 b) at their respective second, upper ends are pivotally connected to respective joints (191; 193).

[0044] The rear leg assembly comprises two substantially parallel rear leg side members (140 a, 140 b) pivotally interconnected at their respective first, lower ends to opposite respective ends of a substantially transverse member (141) by means of respective swivelling corner joints (150 a, 150 b). At their respective second, upper ends, the rear leg side members (140 a, 140 b) are pivotally connected to respective joints (191; 193).

[0045] As can best be seen from FIGS. 3, 4 and 7, the seat side members (121 a, 121 b) are telescopic and so arranged that said seat cross member (120) is movable.

[0046] A central aspect of the chair according to the invention is the straps (430, 440) which extend around the chair frame (100) and preferably run across the said substantially transverse members (110, 120, 131, 141) so as to maintain the chair in an unfolded state. The straps, which transfer all tensile forces, are joined in a buckle (435) and are fastened to the members (110, 120, 131, 141) in such manner that the elements can rotate freely about the respective members.

[0047] The swivelling corner joints (150 a, 150 b) comprise an offset corner joint (150 a) having a pivot point which is drawn back some distance from the pivot point of a second corner joint (150 b). This distance is preferably greater than or equal to the respective external diameter of the members (111 a,b, 121 a,b, 130 a,b, 140 a,b).

[0048] The joints (190; 193) are so arranged that the back side members (1 a, 111 b) are rotatable in the vertical plane in order, when folded, to be close to, and substantially parallel with, said leg assembly.

[0049] In one embodiment, the seat joints (190) and the back joints (191) are substantially coincident and form one combined joint (193).

[0050] In one embodiment the seat joint (190) is positioned at a distance from the back joint (191).

[0051] As can best be seen from FIGS. 2, 4, 6 and 7, the back side members (111 a, 111 b), the front and rear leg side members (130 a, 130 b, 140 a, 140 b), respectively, and the corner joints (150 a, 150 b) are combined in such manner that all respective pairs of side members and corner joints are of equal length.

[0052]FIG. 6 shows that the back side members (111 a, 111 b), the seat side members (121 a, 121 b), the front leg side members (130 a, 130 b) and the rear leg side members (140 a, 140 b) in combination with said corner joints (150 a, 10 b) are of equal length when the chair is in a partly folded state.

[0053] The back joint (191) and/or the combined joint (193) is so arranged that respective pairs of the back side members (111 a, 111 b) and the front leg side members (130 a, 130 b) are substantially axially oriented relative to each other when the chair is unfolded, as shown in particular in FIGS. 3a-3 b. Furthermore, the joints (191; 193) are so arranged that respective pairs of the back side members (111 a, 111 b) and the front leg side members (130 a, 130 b) are oriented substantially parallel to one another when the chair is folded (FIGS. 3c-3 d).

[0054] The seat, back and combined joints (190, 191; 193) are so arranged that the back side members (111 a, 111 b), the seat side members (121 a, 121 b), the front leg side members (130 a, 130 b) and the rear leg side members (140 a, 140 b) are oriented substantially parallel to each other when the chair is folded.

[0055] The corner joints (150 a, 150 b) are so arranged that the back cross member (110), the seat cross member (120), the front leg cross member (131) and the rear leg cross member (141) are oriented parallel to one another when the chair is folded.

[0056] A method of folding the chair according to the invention can be carried out by first loosening the tension lock on the back and taking the strap right out. The back (or the members to which the back is secured), which can be described as a U-shaped frame portion supported in a joint on each side of the chair, is moved forward through an arc so that it lies against the frame portion to which the front part of the seat is secured. This frame portion, to which the front edge of the seat is secured, is when unfolded considerably shorter than the others and is pulled out by means of an adapted telescopic means so that it becomes as long as the back frame portion. These two frame portions, which are now of equal length and rest against each other, are moved further down towards the front legs (also a U-shaped frame portion). These will then describe three U-shaped frame portions which lie parallel to and snugly against one another.

[0057] The rear legs of the chair, which can also be described as a U-shaped frame portion like those described above are moved forward through an arc towards the front legs. Now there will be four U-shaped frame portions of equal size which lie parallel against one another. The piece of cloth and straps will now hang loosely.

[0058] All four U-shaped frame members have identical joints in the corners where the axes are now coincident. The arms on the right-hand side can thus be folded in towards the middle at the same time, as can the arms on the left-hand side. The movement can be compared with folding the side pieces of a standard pair of spectacles. The joints are so arranged that the arms from one side lie on top of the arms from the other side. Altogether, this will be a compact “package” with four parallel U-shaped frame portions in three layers.

[0059] The piece of cloth and the straps which hang loosely can then be wrapped around the whole of this “package”. Lastly, the roll is put in an accompanying case for storage and/or transport.

[0060] In one embodiment, the chair according to the invention has a sitting height of about 35 cm. When folded it is an almost cylindrical “package” which is about 50 cm in length and about 6 cm in diameter.

[0061] The chair according to the invention can be used in a number of different situations. In one embodiment the chair has a height which is almost equal to that of conventional chairs; in another embodiment it is useful as, for example, a beach chair; whilst in a third embodiment—where the back is not collapsible—when folded it is almost like a conventional deck chair.

[0062] Because of its light weight and compact form when folded, the chair according to the invention is particularly suitable for use when camping, at sea, when backpacking etc. The chair can easily be packed and/or stowed, e.g., on a bicycle, in a backpack, in a canoe or the like. 

1. A folding chair, comprising a frame (100), a piece of cloth (400) and fastening and tensioning devices, comprising: a seat frame having two substantially parallel seat side members (121 a, 121 b), pivotally interconnected at their respective first, outer ends to opposite respective ends of a substantially transverse seat cross member (120) by means of respective swivelling corner joints (150 a, 150 b), which said seat side members (121 a, 121 b) at their respective second, inner ends are pivotally connected to respective seat or combined joints (190; 193); a back frame comprising two substantially parallel back side members (111 a, 111 b), pivotally interconnected at their respective first, upper ends to opposite respective ends of a substantially transverse back cross member (110) by means of respective swivelling corner joints (150 a, 150 b); a front leg assembly comprising two substantially parallel front leg side members (130 a, 130 b), pivotally interconnected at their respective, first lower ends to opposite respective ends of a substantially transverse front leg cross member (131) by means of respective swivelling corner joints (150 a, 150 b); a rear leg assembly comprising two substantially parallel rear leg side members (140 a, 140 b), pivotally interconnected at their respective, first lower ends to opposite respective ends of a substantially transverse rear leg cross member (141) by means of respective swivelling corner joints (150 a, 150 b), which said rear leg side members (140 a, 140 b) at their respective second, upper ends are pivotally connected to said respective seat or combined joints (190; 193), wherein the chair comprises tension-absorbing elements (430, 435, 440) which extend around the chair frame (100) and preferably run across the said substantially transverse members (110, 120, 131, 141) so as to maintain the chair in an unfolded state; wherein the chair is characterised in that: said seat side members (121 a, 121 b) are telescopic and so arranged that said seat cross member (120) is movable; said corner joints (150 a, 150 b) comprise an offset corner joint (150 a) having a pivot point which is drawn back some distance from the pivot point of a second corner joint (150 b); and said seat frame, back frame, front and rear leg assemblies are all pivotally interconnected to substantially transverse members by means of pivotal joints.
 2. A folding chair according to claim 1, characterised in that the tension-absorbing elements (430, 440) are fastened to said members (110, 120, 131, 141) in such manner that the elements can rotate freely about the respective members.
 3. A folding chair according to claim 1, characterised in that said seat or combined joints (190, 193) are so arranged that the back side members (111 a, 111 b) of the back frame are rotatable in the vertical plane in order, when folded, to be close to, and substantially parallel with, said leg assembly.
 4. A folding chair according to claim 1, characterised in that said back side members (111 a, 111 b) at their respective second, lower ends are pivotally connected to respective back or combined joints (191; 193).
 5. A folding chair according to claim 1, characterised in that said front leg side members (130 a, 130 b) at their respective second, upper ends are pivotally connected to respective back or combined joints (191; 193).
 6. A folding chair according to claim 1, characterised in that said distance is greater than or equal to the respective external diameter of the members (111 a,b, 121 a,b, 130 a,b, 140 a,b).
 7. A folding chair according to claim 1, characterised in that said seat joint (190) and back joint (191) are substantially coincident and form one combined joint (193).
 8. A folding chair according to claim 1, characterised in that said seat joint (190) is positioned at a distance from the back joint (191).
 9. A folding chair according to claim 1, characterised in that said back and leg side members (111 a, 111 b, 130 a, 130 b, 140 a, 140 b) and said corner joints (150 a, 150 b) are combined in such manner that all respective pairs of side members and corner joints are of equal length.
 10. A folding chair according to claim 1, characterised in that said side members (11 a, 111 b, 121 a, 121 b, 130 a, 130 b, 140 a, 140 b) in combination with said corner joints (150 a, 150 b) are of equal length when the chair is folded.
 11. A folding chair according to claim 1, characterised in that said seat joints (191) or the combined joints (193) are so arranged that respective pairs of the back side members (111 a, 111 b) and the front leg side members (130 a, 130 b) are substantially axially oriented relative to one another when the chair is unfolded.
 12. A folding chair according to claim 1, characterised in that said seat or combined joints (191; 193) are so arranged that respective pairs of the back side members (111 a, 111 b) and the front leg side members (130 a, 130 b) are oriented substantially parallel to one another when the chair is folded.
 13. A folding chair according to claim 1, characterised in that said seat, back and combined joints (190, 191; 193) are so arranged that the members (111 a, 111 b, 121 a, 121 b, 130 a, 130 b, 140 a, 140 b) are oriented substantially parallel to each other when the chair is folded.
 14. A folding chair according to claim 1, characterised in that said corner joints (150 a, 150 b) are so arranged that the members (110, 120, 131, 141) are oriented substantially parallel to one another when the chair is folded. 